=============================
Storage Cluster Quick Start
=============================
If you haven't completed your `Preflight Checklist`_, do that first. This
**Quick Start** sets up a :term:`Ceph Storage Cluster` using ``ceph-deploy``
on your admin node. Create a three Ceph Node cluster so you can
explore Ceph functionality.
.. include:: quick-common.rst
As a first exercise, create a Ceph Storage Cluster with one Ceph Monitor and two
Ceph OSD Daemons. Once the cluster reaches a ``active + clean`` state, expand it
by adding a third Ceph OSD Daemon, a Metadata Server and two more Ceph Monitors.
For best results, create a directory on your admin node for maintaining the
configuration files and keys that ``ceph-deploy`` generates for your cluster. ::
mkdir my-cluster
cd my-cluster
The ``ceph-deploy`` utility will output files to the current directory. Ensure you
are in this directory when executing ``ceph-deploy``.
.. important:: Do not call ``ceph-deploy`` with ``sudo`` or run it as ``root``
if you are logged in as a different user, because it will not issue ``sudo``
commands needed on the remote host.
.. topic:: Disable ``requiretty``
On some distributions (e.g., CentOS), you may receive an error while trying
to execute ``ceph-deploy`` commands. If ``requiretty`` is set
by default, disable it by executing ``sudo visudo`` and locate the
``Defaults requiretty`` setting. Change it to ``Defaults:ceph !requiretty`` to
ensure that ``ceph-deploy`` can connect using the ``ceph`` user and execute
commands with ``sudo``.
Create a Cluster
================
If at any point you run into trouble and you want to start over, execute
the following to purge the configuration::
ceph-deploy purgedata {ceph-node} [{ceph-node}]
ceph-deploy forgetkeys
To purge the Ceph packages too, you may also execute::
ceph-deploy purge {ceph-node} [{ceph-node}]
If you execute ``purge``, you must re-install Ceph.
On your admin node from the directory you created for holding your
configuration details, perform the following steps using ``ceph-deploy``.
#. Create the cluster. ::
ceph-deploy new {initial-monitor-node(s)}
Specify node(s) as hostname, fqdn or hostname:fqdn. For example::
ceph-deploy new node1
Check the output of ``ceph-deploy`` with ``ls`` and ``cat`` in the current
directory. You should see a Ceph configuration file, a monitor secret
keyring, and a log file for the new cluster. See `ceph-deploy new -h`_
for additional details.
#. Change the default number of replicas in the Ceph configuration file from
``3`` to ``2`` so that Ceph can achieve an ``active + clean`` state with
just two Ceph OSDs. Add the following line under the ``[global]`` section::
osd pool default size = 2
#. If you have more than one network interface, add the ``public network``
setting under the ``[global]`` section of your Ceph configuration file.
See the `Network Configuration Reference`_ for details. ::
public network = {ip-address}/{netmask}
#. Install Ceph. ::
ceph-deploy install {ceph-node}[{ceph-node} ...]
For example::
ceph-deploy install admin-node node1 node2 node3
The ``ceph-deploy`` utility will install Ceph on each node.
**NOTE**: If you use ``ceph-deploy purge``, you must re-execute this step
to re-install Ceph.
#. Add the initial monitor(s) and gather the keys::
ceph-deploy mon create-initial
Once you complete the process, your local directory should have the following
keyrings:
- ``{cluster-name}.client.admin.keyring``
- ``{cluster-name}.bootstrap-osd.keyring``
- ``{cluster-name}.bootstrap-mds.keyring``
- ``{cluster-name}.bootstrap-rgw.keyring``
.. note:: The bootstrap-rgw keyring is only created during installation of clusters
running Hammer or newer
.. note:: If this process fails with a message similar to
"Unable to find /etc/ceph/ceph.client.admin.keyring", please ensure that the IP
listed for the monitor node in ceph.conf is the Public IP, not the Private IP.
#. Add two OSDs. For fast setup, this quick start uses a directory rather
than an entire disk per Ceph OSD Daemon. See `ceph-deploy osd`_ for
details on using separate disks/partitions for OSDs and journals.
Login to the Ceph Nodes and create a directory for
the Ceph OSD Daemon. ::
ssh node2
sudo mkdir /var/local/osd0
exit
ssh node3
sudo mkdir /var/local/osd1
exit
Then, from your admin node, use ``ceph-deploy`` to prepare the OSDs. ::
ceph-deploy osd prepare {ceph-node}:/path/to/directory
For example::
ceph-deploy osd prepare node2:/var/local/osd0 node3:/var/local/osd1
Finally, activate the OSDs. ::
ceph-deploy osd activate {ceph-node}:/path/to/directory
For example::
ceph-deploy osd activate node2:/var/local/osd0 node3:/var/local/osd1
#. Use ``ceph-deploy`` to copy the configuration file and admin key to
your admin node and your Ceph Nodes so that you can use the ``ceph``
CLI without having to specify the monitor address and
``ceph.client.admin.keyring`` each time you execute a command. ::
ceph-deploy admin {admin-node} {ceph-node}
For example::
ceph-deploy admin admin-node node1 node2 node3
When ``ceph-deploy`` is talking to the local admin host (``admin-node``),
it must be reachable by its hostname. If necessary, modify ``/etc/hosts``
to add the name of the admin host.
#. Ensure that you have the correct permissions for the
``ceph.client.admin.keyring``. ::
sudo chmod +r /etc/ceph/ceph.client.admin.keyring
#. Check your cluster's health. ::
ceph health
Your cluster should return an ``active + clean`` state when it
has finished peering.
Operating Your Cluster
======================
Deploying a Ceph cluster with ``ceph-deploy`` automatically starts the cluster.
To operate the cluster daemons with Debian/Ubuntu distributions, see
`Running Ceph with Upstart`_. To operate the cluster daemons with CentOS,
Red Hat, Fedora, and SLES distributions, see `Running Ceph with sysvinit`_.
To learn more about peering and cluster health, see `Monitoring a Cluster`_.
To learn more about Ceph OSD Daemon and placement group health, see
`Monitoring OSDs and PGs`_. To learn more about managing users, see
`User Management`_.
Once you deploy a Ceph cluster, you can try out some of the administration
functionality, the ``rados`` object store command line, and then proceed to
Quick Start guides for Ceph Block Device, Ceph Filesystem, and the Ceph Object
Gateway.
Expanding Your Cluster
======================
Once you have a basic cluster up and running, the next step is to expand
cluster. Add a Ceph OSD Daemon and a Ceph Metadata Server to ``node1``.
Then add a Ceph Monitor to ``node2`` and ``node3`` to establish a
quorum of Ceph Monitors.
.. ditaa::
/------------------\ /----------------\
| ceph-deploy | | node1 |
| Admin Node | | cCCC |
| +-------->+ mon.node1 |
| | | osd.2 |
| | | mds.node1 |
\---------+--------/ \----------------/
|
| /----------------\
| | node2 |
| | cCCC |
+----------------->+ |
| | osd.0 |
| | mon.node2 |
| \----------------/
|
| /----------------\
| | node3 |
| | cCCC |
+----------------->+ |
| osd.1 |
| mon.node3 |
\----------------/
Adding an OSD
-------------
Since you are running a 3-node cluster for demonstration purposes, add the OSD
to the monitor node. ::
ssh node1
sudo mkdir /var/local/osd2
exit
Then, from your ``ceph-deploy`` node, prepare the OSD. ::
ceph-deploy osd prepare {ceph-node}:/path/to/directory
For example::
ceph-deploy osd prepare node1:/var/local/osd2
Finally, activate the OSDs. ::
ceph-deploy osd activate {ceph-node}:/path/to/directory
For example::
ceph-deploy osd activate node1:/var/local/osd2
Once you have added your new OSD, Ceph will begin rebalancing the cluster by
migrating placement groups to your new OSD. You can observe this process with
the ``ceph`` CLI. ::
ceph -w
You should see the placement group states change from ``active+clean`` to active
with some degraded objects, and finally ``active+clean`` when migration
completes. (Control-c to exit.)
Add a Metadata Server
---------------------
To use CephFS, you need at least one metadata server. Execute the following to
create a metadata server::
ceph-deploy mds create {ceph-node}
For example::
ceph-deploy mds create node1
.. note:: Currently Ceph runs in production with one metadata server only. You
may use more, but there is currently no commercial support for a cluster
with multiple metadata servers.
Add an RGW Instance
-------------------
To use the :term:`Ceph Object Gateway` component of Ceph, you must deploy an
instance of :term:`RGW`. Execute the following to create an new instance of
RGW::
ceph-deploy rgw create {gateway-node}
For example::
ceph-deploy rgw create node1
.. note:: This functionality is new with the **Hammer** release, and also with
``ceph-deploy`` v1.5.23.
By default, the :term:`RGW` instance will listen on port 7480. This can be
changed by editing ceph.conf on the node running the :term:`RGW` as follows:
.. code-block:: ini
[client]
rgw frontends = civetweb port=80
To use an IPv6 address, use:
.. code-block:: ini
[client]
rgw frontends = civetweb port=[::]:80
Adding Monitors
---------------
A Ceph Storage Cluster requires at least one Ceph Monitor to run. For high
availability, Ceph Storage Clusters typically run multiple Ceph
Monitors so that the failure of a single Ceph Monitor will not bring down the
Ceph Storage Cluster. Ceph uses the Paxos algorithm, which requires a majority
of monitors (i.e., 1, 2:3, 3:4, 3:5, 4:6, etc.) to form a quorum.
Add two Ceph Monitors to your cluster. ::
ceph-deploy mon add {ceph-node}
For example::
ceph-deploy mon add node2
ceph-deploy mon add node3
Once you have added your new Ceph Monitors, Ceph will begin synchronizing
the monitors and form a quorum. You can check the quorum status by executing
the following::
ceph quorum_status --format json-pretty
.. tip:: When you run Ceph with multiple monitors, you SHOULD install and
configure NTP on each monitor host. Ensure that the
monitors are NTP peers.
Storing/Retrieving Object Data
==============================
To store object data in the Ceph Storage Cluster, a Ceph client must:
#. Set an object name
#. Specify a `pool`_
The Ceph Client retrieves the latest cluster map and the CRUSH algorithm
calculates how to map the object to a `placement group`_, and then calculates
how to assign the placement group to a Ceph OSD Daemon dynamically. To find the
object location, all you need is the object name and the pool name. For
example::
ceph osd map {poolname} {object-name}
.. topic:: Exercise: Locate an Object
As an exercise, lets create an object. Specify an object name, a path to
a test file containing some object data and a pool name using the
``rados put`` command on the command line. For example::
echo {Test-data} > testfile.txt
rados mkpool data
rados put {object-name} {file-path} --pool=data
rados put test-object-1 testfile.txt --pool=data
To verify that the Ceph Storage Cluster stored the object, execute
the following::
rados -p data ls
Now, identify the object location::
ceph osd map {pool-name} {object-name}
ceph osd map data test-object-1
Ceph should output the object's location. For example::
osdmap e537 pool 'data' (0) object 'test-object-1' -> pg 0.d1743484 (0.4) -> up [1,0] acting [1,0]
To remove the test object, simply delete it using the ``rados rm``
command. For example::
rados rm test-object-1 --pool=data
As the cluster evolves, the object location may change dynamically. One benefit
of Ceph's dynamic rebalancing is that Ceph relieves you from having to perform
the migration manually.
.. _Preflight Checklist: ../quick-start-preflight
.. _Ceph Deploy: ../../rados/deployment
.. _ceph-deploy install -h: ../../rados/deployment/ceph-deploy-install
.. _ceph-deploy new -h: ../../rados/deployment/ceph-deploy-new
.. _ceph-deploy osd: ../../rados/deployment/ceph-deploy-osd
.. _Running Ceph with Upstart: ../../rados/operations/operating#running-ceph-with-upstart
.. _Running Ceph with sysvinit: ../../rados/operations/operating#running-ceph-with-sysvinit
.. _CRUSH Map: ../../rados/operations/crush-map
.. _pool: ../../rados/operations/pools
.. _placement group: ../../rados/operations/placement-groups
.. _Monitoring a Cluster: ../../rados/operations/monitoring
.. _Monitoring OSDs and PGs: ../../rados/operations/monitoring-osd-pg
.. _Network Configuration Reference: ../../rados/configuration/network-config-ref
.. _User Management: ../../rados/operations/user-management